Bicycle saddle is mounted on a seat post which is telescopically fitted within a seat tube extending upwardly from the bottom bracket which journals the pedal crank. Conventionally, the top end of the seat tube is split on the backside and it has a heavy U-shaped collar with a long seat clamp bolt which can be tightened to grip the seat post and hold the saddle at a preferred height.
These conventional clamps and the bolts and bolt tightening levers often used with them, are unattractive, and involve external components which take up scarce room beneath the seat.
Applicant is aware of at least one attempt to provide a seat post mechanism which was wholly contained within the frame tubing, without any of the conventional external components, but this involved wedging high angle cam surfaces directly against the seat post, causing it to stick when the cam surfaces would not release.